Bessemer converter



Oct. 18, 1949. H. L. McFEATERS BESSEMER CONVERTER Filed March 5, 1946 l r. I

{ M W NTOR +32% H ATTOR Patented Oct. 18, 1949 BESSEMER CONVERTER Harry L. McFeaters, New Castle, Pa., asslgnor to Pennsylvania Engineering Corporation, a corporation of Pennsylvania Application March 5, 1946, Serial No. 652,119

4 Claims. 1

This invention relates to Bessemer converters and more particularly to bottom blow converters of the tilting type.

. Present day converters in commercial use are mainly of the bottom blow tilting type and all are circular in cross section, although in some the nose portion and mouth are eccentrically arranged.

These present day converters are either mainly cylindrical and therefore of constant cross sectional area to well above the longitudinal center, or are of egg or pear shape and start to decrease in cross sectional area well below such center, and it is my belief that the expanding effervescing mass of molten metal and gases extends to a point well above the longitudinal center of such converters. I believe this constant area in one case and decreasing area in the other is a primary cause of excessive spitting and there- 'fore loss of metal through the mouth of the converter.

While some early patents disclose stationary converters having a body of circular cross section and having such contour above the normal metal line that the effervescing mass could expand to peak volume below the center line of such converter, so far as I know there is no disclosure in the art, of a tilting Bessemer converter of circular cross section which curves or bulges outwardly from the tops of the tuyres to the center line of the converter-the trunnion line-so that the efiervescing mass will reach its peak volume at or below such line, where it has room or space within which to expand and therefore have its velocity reduced.

This is probably due to the fact that outward curving or bulging of the converter side wallswith the greatest diameter at the trunnion line or at the plane which includes the trunnion axes and is perpendicular to the longitudinal axis of the converter-increases the distance between the trunnions, and therefore the stresses to which the central section of the converter shell is subjected during tilting. In order to avoid this increase in distance between the trunnions, at least one early patent decreases this distance by fiattening the sides to which the trunnions are se- --cu.red.

An object of this invention is to produce a tilting' Bessemer converter of increasing circular cross sectional area from the tuyeres to the longitudinal center of the converter body so that the efiervescing mass of molten metal and gases can 2 reach its peak volume at or below such longitudinal center.

Another object is to produce a tilting converter in which the Bessemer process of producing steel can be carried out with less spitting and less waste of metal than with present commercial tilting converters. M

Another object is to produce a tilting Bessemer converter in which a cleaner steel can be produced than with the accepted type of converter.

A still further object is to produce a tilting Bessemer converter in which a greater slag volume can be used than is possible in present day tilting converters of the same capacity.

A still further object is to produce a tilting Bessemer converter in which a more intimate mixture of blast air and molten metal can be obtained than with present day commercial types of tilting converters, and with less oxidation of the metal.

A further object is to produce an improved shell structure for tilting Bessemer converters. I

These and other objects I attain by means of the converter described in the specification and illustrated in the drawings accompanying and forming part of this application.

In the drawings:

Figure 1 is a front view in section except for the nose which is in elevation, of a Bessemer converter embodying this invention.

Fig. 2 is a horizontal sectional view taken on line II-II of Fi 1; and

Fig. 3 is a fragmentary sectional view of a modified form of the central section of the converter shell for receiving a removable trunnion ring of usual design.

In order to attain the objects of thisinvention, the body of my converter curves or bulges outwardly from its ends to a plane which includes its longitudinal center, and is perpendicular to its major axis and adjacent such plane has a zone which extends substantially an equal distance above and below said plane and approximates a central section of a hollow sphere. This, zone takes in or embraces at least one, third of the body and preferably about one half.

The cross sectional area of the converter body thus increases from the top of the tuyres to its longitudinal center and from such longitudinal center gradually decreases in cross sectional area to the nose portion thereof.

The increase in area to the longitudinal center--the trunnion line-as is hereinafter pointed out, permits free circulation of the metal of the bath, and during the boil, afi'ords space so that the eflervescing mass of molten metal and gases can reach its peak volume within an expanding area as contrasted with a. decreasing area as in pear shaped converters, or a constant area as in cylindrical converters.

While thisoonverter body of increasing area up to the trunnion line subjects the body shell to increased stresses, I make ample provision for such increased stresses by forming the central section or zone of the shell so that it approximates a central section or a hollow sphere and I utilize plate material in themake-up of the shell of such zone which is substantially twice the thickness of the plate material in the remainder of the shell.

The converter chosen as an embodiment of this invention is of the bottom blow, tilting type and as usual comprises .a bottom H], a body H, and a nose l2.

The bottom comprises a wind box 1'3 and a central circular group of tuyeres M. The tuyere openings l5 shown in Fig.1 have been omitted from Fig. 2 for the purpose of simplification.

The converter body shell as well as the tuyere section of the bottom is fabricated from metal plate material and embodies both riveted and welded construction.

The body shell as disclosed in Fig; 1 curves or bulges outwardly from its ends to its longitudinal center; its bottom end being numbered 16 and its top end where it joins the nose portion being numbered l1.

-Ihe body is provided with a refractory lining M which is of substantially uniform thickness throughout and parallels the inner surface of the body shell. In a 25 ton converter, the refractory .lining is substantially two feet in thickness throughout. The body shell and the refractory lining both have their greatest internal diameter at the longitudinal center line of the converter, the trunnion line.

. The body shell comprises a centrally located zone 18 which extends above the longitudinal center to a point 20 and below such center to a point 2|. Points 20 and 2| are preferably equally spaced from. the longitudinal center. In Fig. 1, the trunnion castings 22 are shown secured to the body shell at zone IS, with the axes of the trunnions 23 and 24 intersecting such longitudinal center and such castings are preferably secured to the shell plates by rivets (not shown) as will be understood.

The shell of the converter nose, the body shell above zone l9 as well as the bodyshell below such zone are made of plate material of the thickness usually used in converters of the same capacity. That is, in aconverter of 25 ton capacity, these shell portions will usually be made from one inch plate material. The shell of zone I9 is made from plate material of substantially twice the thickness of that of the other portions of the bodyshell and nose shell and in a converter of 25 ton capacity, I prefer to make the shell of zone [9 of plate material having a thickness of two inches.

The upper portion of the body shell is secured to the upper part of the shell of zone l9 by means of inner and outer straps 25 and 26 formed of plate material, and an inner spacer plate 2']. These straps and the spacer are secured to the upper portion of the body shell and the shell of me ill preferably by means of rivets (not shown). The lower part of the shell of zone 19 is secured 4 to the lower part of the body shell in a similar manner as indicated at 28.

The shell of zone I9 is reinforced by relatively heavy bar members 29 and 30. These are edge bent to form rings, and ring bar 29 is welded to the shell of zone l9 by means of Welds 3| and 32, while ring bar 30 is welded to the shell of zone Is by welds 33 and 34. Ring bar 29 islocated immediately above the trunnion pads or castings 22 while ring bar 30 is located immediately below trunnion pads or castings 22.

' trunnion ring 36 .of usual construction.

" above such longitudinal center.

In Fig. '3 of the drawings, the shell of zone l9 has trunnion ring brackets 35 secured thereto preferably by rivets and these brackets, which encircle the converter shell at zone H! are adapted to co-operate in supporting the converter on a While the .trunnions are not shown in this View, it being taken from the trunnion axes, the converter body is secured to the trunnion ring by means of the usual bolts 31 and the converter is held in position by adjusting blocks 38 and wedges 39.

The air blast causes the molten metal to be driven upwardly as a more or less well defined stream having a diameter approximating the diameter of the centrally located area defined by the group of tuyeres which in a 25 ton converter would be approximately 7 feet three inches. Prior to the boil this upward moving stream, as it reaches the top of the bath, mushrooms or flows outwardly in all directions and thence flows freely downwardly around the upward moving portion of this stream. The metal then flows inwardly uniformly across the bottom where it is again picked up by the air blast.

In a 25 ton converter, the internal diameter of the lining of the body at its lower end is approximately 9 feet -8 inches and at its longitudinal center, the internal diameter of the lining is approximately 11 feet 7 inches. This outward bulging or curving of the converter sides (with its greatest diameter at the longitudinal center of the converter) facilitates the free circulation of the metal of the bath, and because of this free circulation, the oxygen of the air blast has the opportunity of acting uniformly on all the metal and materials and no part of the metal .is oxidized more than another part.

During the boil the annular surrounding space derived by this outward curving or bulging of the converter, provides room for the efferverscing mass of molten metal and gases to reach its peak volume due to expansion, without rising This annular space by providing room for expansion reduces the velocity of the boiling mass and thus avoids excessive spitting and loss of metal and also improves the refining process by insuring a more intimate mixture oi the oxygen of the blast and the metallic elements of the bath.

What I claim as new and desire to secure by Letters Patent is:

1. In a Bessemer converter having a group of upwardly discharging tuyres in its bottom,

having a body above such tuyeres comprising a metal shell formed of plate material and a refractory lining of substantially uniform thickness; such metal shell having its greatest diameter at its longitudinal center and being curved outwardly from its ends to .a plane which includes its longitudinal center and is perpendicular to its major axis; such shell having a centrally located zone embracing substantially one third of the body shell, approximating a central section 5 of a hollow sphere and having a shell thickness substantially twice that of the remainder of the body shell, and trunnion means secured to the body shell within such centrally located zone.

2. A structure as defined in claim 1, in which the shell of such centrally located zone is reinforced by spaced-apart bars, edge bent to form rings which are welded to the shell of such zone above and below such trunnion means.

3. A structure as defined in claim 1, in which 0 the trunnion means takes the form of a trunnion ring equipped with trunnions and is removably secured in position.

4. A structure as designed in claim 1, in which the shell of such centrally located zone is reinl5 forced by spaced-apart bar rings edge welded to such shell and in which the trunnion means takes the form of trunnions having pads which are directly secured to such shell between such rings.

HARRY L'. MCFEATERS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 49,055 Bessemer July 25, 1865 117,248 Bessemer July 25, 1871 358,559 Laureau Mar. 1, 1887 741,505 Kirk Oct. 13, 1903 942,973 Peirce Dec. 14, 1909 1,505,281 Nagelvoort Aug. 19, 1924 2,079,872 Quinn -1. May 11, 1937 2,265,511 Brassert Dec. 9, 1941 FOREIGN PATENTS Number Country Date 13,696 Germany May 14, 1881 3,530 Great Britain Sept. 3, 1879 7,021 Great Britain Dec. 17, 1897 

